U.S. Pat. No. 6,169,198 describes the process of hydrocyanation (reaction with HCN) of BD to prepare ADN, and explains that the process can generally be divided into three steps. First, mononitriles such as 3-pentenenitrile (3-PN) are formed by the reaction of HCN with BD, along with other nitriles, including isomers which must be isomerized in subsequent steps to achieve the desired straight chain ADN as a final product. Second is the isomerization of species such as 2-methyl-3-butenenitrile (2M3BN). Third is a second hydrocyanation of the pentenenitriles to yield the desired ADN.
U.S. Pat. No. 5,981,722 describes and exemplifies a new class of catalysts for such transformations by the use of diphosphite nickel complexes for the hydrocyanation and isomerizations. This class of catalysts is characterized by greater catalytic activity and resistence to HCN-derived degradation reactions.
U.S. Pat. No. 7,470,805 describes a process of hydrocyanation of diolefins in the presence of a catalytic system comprising a transition metal and mono- and pluri-dentate organophosphorus ligands. According to this, the use of a mixture of two ligands, monodentate and pluri (bi and/or tri)dentate, enables the pluridentate ligand to be preserved in the reaction milieu.
Monodentate and bidentate phosphorus-based ligands, depicted as formulae (7) and (8), and (3), respectively, as the structures are termed in U.S. Pat. No. 7,629,484, can be used in preparation of a transition metal-organophosphorus catalyst for reactions such as hydrocyanation.

U.S. Pat. No. 7,659,422 describes a hydrocyanation process to produce ADN from BD with control of i) the overall feed molar ratio of 2-pentenenitriles to all unsaturated nitriles and ii) the overall feed molar ratio of HCN to all unsaturated nitriles. An example is given as a reaction mixture comprising a Lewis acid promoter (FeCl2) and bidentate Ligand B, which is as depicted as identical to Compound (3) above.
U.S. Pat. No. 7,977,502 describes an integrated, continuous process for the production of 3-PN, the refining of 3-PN and the refining of 2M3BN by a process comprising contacting a feed stream in a reaction zone, maintaining residence time to convert about 95% or more of the HCN, distilling to create various streams.
U.S. Published Patent Application No. 2011/0196168 describes nickel-containing solids comprising nickel metal derived from basic nickel carbonates (BNCs) which are highly reactive with both monodentate and Bidentate phosphorus-containing ligands in forming nickel metal complexes, which can be for producing pentenenitriles and dinitriles by hydrocyanation.